V4L/DVB (11086): au0828: rename macro for currently non-function VBI support

The VBI support or the au0828 has the framework written but it does not yet
work.  Rename the macro per Mauro's request.

Signed-off-by: Devin Heitmueller <dheitmueller@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>